Sodium bicarbonate (NaHCO3) is a product with a wide range of interesting properties and a very wide range of applications from high tech ingredients for the pharmaceutical industry to the human food and animal feed industry.
Sodium bicarbonate can be produced by the carbonation of sodium carbonate. In Europe, the carbonation is usually performed in situ in the soda ash plants from CO2 coproduced during the production of soda ash (mainly the CO2 generation in the lime kilns). In the USA, the carbonation is usually performed in separate plants which purchase independently the soda ash and the CO2 and combine them.
Sodium bicarbonate wet cake is traditionally dried by using conventional rotary steam tube dryers. Such methods involve high temperature dehydration and steam pressure up to 35 atm. The dried material usually has high bulk density and the crystals resulting from this process usually have irregular particle size distribution and dendritic structures, which are physically weak and readily disintegrate into finer fragments on handling. Furthermore, at higher temperatures, sodium bicarbonate tends to be converted into sodium carbonate.
It is an object of the invention to provide sodium bicarbonate particles with a high specific surface area. It is also an object of the invention to provide a process for preparing sodium carbonate particles with a high specific surface.